1 Samuel 24:11

There is neither evil nor transgression in mine hand— Instead of taking away Saul's life, David only privately cut off the skirt of his robe. His protestation of his innocence, and having no intention to deprive Saul of his crown and life, was founded in truth, and verified by the most authentic facts. Nor was his being in arms a contradiction to it; unless a man's being in arms to preserve his life, and not to oppose his friend, argues him guilty of rebellion; or unless when a tyrant tells a man he will have his life, such a person is bound to hold out his throat to the Lord's anointed, and humbly bid him cut it at his pleasure. David did not seem to be of this opinion; and therefore kept himself in arms, and upon his defence, because he had no other possible means of safety.